Ergheo meteorite, Lower Shabelle Region, Somaliai
| Regional Level Types | |
|---|---|
| Ergheo meteorite | Meteorite Fall Location |
| Lower Shabelle Region | Region |
| Somalia | Country |
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Latitude & Longitude (WGS84):
1° 10' 22'' North , 44° 5' 35'' East
Latitude & Longitude (decimal):
Locality type:
Meteorite Class:
Meteoritical Society Class:
Köppen climate type:
Name(s) in local language(s):
, Soomaaliya (الصومال; aṣ-Ṣūmāl)
Ordinary chondrite, veined (L5)
Fell, July 1889; 20.375 kg.
Baldanza described the location of the find as "Ergheo, Brava, Somaliland".
The port town of Brava is now also known as Barawa (Baraawe).
A single stone fell and was left where it lay for several years. The moderately equilibrated interior is characterized by indistinct chondrules with small metal grains. Widespread wavy extinction is present within mineral grains and interstitial maskelynite is ubiquitous. Olivine (Fa~24) and orthopyroxene (Fs~21) compositions are characteristic of the L-chondrite geochemical group. Mineralogically the meteorite is dominated by silicates [>90 vol%] (primarily olivine and pyroxene) accompanied by minor troilite (~6 vol%), and Fe-Ni (~2 vol%) metal. Accessory chromite and other minor silicates and oxides are also reported. Shock indicators include prominent veining, fractured crystals, irregular aggregates of polyhedral chondrules, maskelynite, and plessite. Not surprisingly, significant weathering is often apparent.
K-Ar and Pb,Th:He gas retention ages of 1.023 Ga & 0.61 Ga, respectively, as well as a cosmic-ray exposure (CRE) age of ~24 Ma have been reported. Helium and Argon release ages often reflecting major collisional events, while the CRE age often reflects the meteoroid's final period before earth-encounter.
The L-group of ordinary chondrites (relatively low in total iron) is the largest group of classified witnessed meteorite falls and account for ~45% of the well-classified meteorite falls. The small L5 petrologic type subgroup accounts for ~ 20% of the group. 82 meteorite falls had been classified exactly as L5 chondrites by early June 2017.
The Ergheo mass was well distributed with masses of ~ 1 kg still held by the United States National Museum (Washington) and the British Natural History Museum (NHM) in London. Consequently, it has been been a minor part of a number of studies. Much of the mineralogical and petrographic work was consolidated in the article by Baldanza & Levi-Donati (1971).
Nota bene: The coordinates provided by both the Catalogue of Meteorites (5/e) and the Meteoritical Bulletin Database (June 2017) would place the fall site in the ocean east of Somalia.
Coordinates are approximate only.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsMineral List
6 valid minerals.
Meteorite/Rock Types Recorded
Note: data is currently VERY limited. Please bear with us while we work towards adding this information!
Select Rock List Type
Alphabetical List Tree DiagramDetailed Mineral List:
| ⓘ Chromite Formula: Fe2+Cr3+2O4 Reference: Bunch, T.E., Keil, K. & Snetsinger, K.G. (1967) Chromite composition in relation to chemistry and texture of ordinary chondrites. Geochimica et Cosmochimica Acta 31(10): 1569-1582. (Oct 1967).; Ramdohr, P. (1973) The Opaque Minerals in Stony Meteorites. Elsevier Publishing Company: Amsterdam; London: New York. 245 pages. |
| ⓘ 'Fayalite-Forsterite Series' Description: Olivine composition — (Fa25), Mason 1963, (Fa23.7), Keil & Fredriksson 1964 — typical L-group ordinary chondrites Reference: Merrill, G. P. (1916) Handbook and Descriptive Catalogue of the Meteorite Collections in the U.S. National Museum. Bull. U. S. Natl. Museum, No.94, Washington. 207 pp., 41 pls.; Mason, B. (1963) Olivine in ordinary chondrites. Geochimica et Cosmochimica Acta 27(9): 1011-1023. (Sept 1963).; Keil, K. & Fredriksson, K. (1964) The Fe, Mg, and Ca Distribution in Coexisting Olivines and Rhombic Pyroxenes of Chondrites. Journal of Geophysical Research Atmospheres 69 (16): 3487-3515. (August 1964).; Baldanza, B. & Levi-Donati, G.R. (1971) Evidence of Shock-Metamorphic Effects in the Ergheo Meteorite: Mineralogical Magazine 38(294): 197-204. (June 1971). |
| ⓘ 'Feldspar Group' Reference: Baldanza, B. & Levi-Donati, G.R. (1971) Evidence of Shock-Metamorphic Effects in the Ergheo Meteorite: Mineralogical Magazine 38(294): 197-204. (June 1971). |
| ⓘ 'Glass' Description: Dark brown glass in veins as well as transparent interstitial maskelynite. Reference: Baldanza, B. & Levi-Donati, G.R. (1971) Evidence of Shock-Metamorphic Effects in the Ergheo Meteorite: Mineralogical Magazine 38(294): 197-204. (June 1971). |
| ⓘ Ilmenite Formula: Fe2+TiO3 Description: Peculiar tri-planar twinning in magnetite. Reference: Baldanza, B. & Levi-Donati, G.R. (1971) Evidence of Shock-Metamorphic Effects in the Ergheo Meteorite: Mineralogical Magazine 38(294): 197-204. (June 1971). |
| ⓘ Iron Formula: Fe Reference: Ramdohr, P. (1973) The Opaque Minerals in Stony Meteorites. Elsevier Publishing Company: Amsterdam; London: New York. 245 pages. |
| ⓘ Iron var. Kamacite Formula: (Fe,Ni) Reference: Ramdohr, P. (1973) The Opaque Minerals in Stony Meteorites. Elsevier Publishing Company: Amsterdam; London: New York. 245 pages. |
| ⓘ 'Limonite' Reference: Ramdohr, P. (1973) The Opaque Minerals in Stony Meteorites. Elsevier Publishing Company: Amsterdam; London: New York. 245 pages. |
| ⓘ Magnetite Formula: Fe2+Fe3+2O4 Reference: Baldanza, B. & Levi-Donati, G.R. (1971) Evidence of Shock-Metamorphic Effects in the Ergheo Meteorite: Mineralogical Magazine 38(294): 197-204. (June 1971). |
| ⓘ 'Maskelynite' Reference: Merrill, G. P. (1916) Handbook and Descriptive Catalogue of the Meteorite Collections in the U.S. National Museum. Bull. U. S. Natl. Museum, No.94, Washington. 207 pp., 41 pls.; Baldanza, B. & Levi-Donati, G.R. (1971) Evidence of Shock-Metamorphic Effects in the Ergheo Meteorite: Mineralogical Magazine 38(294): 197-204. (June 1971). |
| ⓘ 'Orthopyroxene Subgroup' Description: Orthopyroxene composition (Fs2o.5), typical of L-group ordinary chondrites. Reference: Merrill, G. P. (1916) Handbook and Descriptive Catalogue of the Meteorite Collections in the U.S. National Museum. Bull. U. S. Natl. Museum, No.94, Washington. 207 pp., 41 pls.; Keil, K. & Fredriksson, K. (1964) The Fe, Mg, and Ca Distribution in Coexisting Olivines and Rhombic Pyroxenes of Chondrites. Journal of Geophysical Research Atmospheres 69 (16): 3487-3515. (August 1964). |
| ⓘ 'Plessite' Reference: Ramdohr, P. (1973) The Opaque Minerals in Stony Meteorites. Elsevier Publishing Company: Amsterdam; London: New York. 245 pages. |
| ⓘ Taenite Formula: (Fe,Ni) Reference: Ramdohr, P. (1973) The Opaque Minerals in Stony Meteorites. Elsevier Publishing Company: Amsterdam; London: New York. 245 pages. |
| ⓘ Troilite Formula: FeS Description: Often in recrystallized polycrystalline masses. Reference: Merrill, G. P. (1916) Handbook and Descriptive Catalogue of the Meteorite Collections in the U.S. National Museum. Bull. U. S. Natl. Museum, No.94, Washington. 207 pp., 41 pls.; Baldanza, B. & Levi-Donati, G.R. (1971) Evidence of Shock-Metamorphic Effects in the Ergheo Meteorite: Mineralogical Magazine 38(294): 197-204. (June 1971).; Ramdohr, P. (1973) The Opaque Minerals in Stony Meteorites. Elsevier Publishing Company: Amsterdam; London: New York. 245 pages. |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 1 - Elements | |||
|---|---|---|---|
| ⓘ | Iron | 1.AE.05 | Fe |
| ⓘ | var. Kamacite | 1.AE.05 | (Fe,Ni) |
| ⓘ | Taenite | 1.AE.10 | (Fe,Ni) |
| Group 2 - Sulphides and Sulfosalts | |||
| ⓘ | Troilite | 2.CC.10 | FeS |
| Group 4 - Oxides and Hydroxides | |||
| ⓘ | Chromite | 4.BB.05 | Fe2+Cr3+2O4 |
| ⓘ | Ilmenite | 4.CB.05 | Fe2+TiO3 |
| ⓘ | Magnetite | 4.BB.05 | Fe2+Fe3+2O4 |
| Unclassified Minerals, Rocks, etc. | |||
| ⓘ | 'Fayalite-Forsterite Series' | - | |
| ⓘ | 'Feldspar Group' | - | |
| ⓘ | 'Glass' | - | |
| ⓘ | 'Limonite' | - | |
| ⓘ | 'Maskelynite' | - | |
| ⓘ | 'Orthopyroxene Subgroup' | - | |
| ⓘ | 'Plessite' | - | |
List of minerals for each chemical element
| O | Oxygen | |
|---|---|---|
| O | ⓘ Chromite | Fe2+Cr23+O4 |
| O | ⓘ Ilmenite | Fe2+TiO3 |
| O | ⓘ Magnetite | Fe2+Fe23+O4 |
| S | Sulfur | |
| S | ⓘ Troilite | FeS |
| Ti | Titanium | |
| Ti | ⓘ Ilmenite | Fe2+TiO3 |
| Cr | Chromium | |
| Cr | ⓘ Chromite | Fe2+Cr23+O4 |
| Fe | Iron | |
| Fe | ⓘ Troilite | FeS |
| Fe | ⓘ Chromite | Fe2+Cr23+O4 |
| Fe | ⓘ Ilmenite | Fe2+TiO3 |
| Fe | ⓘ Magnetite | Fe2+Fe23+O4 |
| Fe | ⓘ Iron var. Kamacite | (Fe,Ni) |
| Fe | ⓘ Taenite | (Fe,Ni) |
| Fe | ⓘ Iron | Fe |
| Ni | Nickel | |
| Ni | ⓘ Iron var. Kamacite | (Fe,Ni) |
| Ni | ⓘ Taenite | (Fe,Ni) |
References
Sort by
Year (asc) Year (desc) Author (A-Z) Author (Z-A) In-text Citation No.Artini, E., Melzi, G. (1898) Intorno ad un meteorite caduto ad Ergheo, presso Brava, nella penisola dei Somali. L'esplorazione commerciale: 12: 403-415.
Artini, E., Melzi, G. (1898) Intorno ad un meteorite caduto ad Ergheo, presso Brava, nella penisola dei Somali. Rendiconti del R. Istituto Lombardo di Scienze e Lettere: 31: 983-995.
Merrill, G.P. (1916) Handbook and Descriptive Catalogue of the Meteorite Collections in the United States National Museum. Bulletin 94, Washington, 207 pages, and 41 plates.
Mason, B. (1963) Olivine in ordinary chondrites. Geochimica et Cosmochimica Acta: 27(9) (Sept. 1963): 1011-1023.
Keil, K., Fredriksson, K. (1964) The Fe, Mg, and Ca Distribution in Coexisting Olivines and Rhombic Pyroxenes of Chondrites. Journal of Geophysical Research-Atmospheres: 69(16) (August 1964): 3487-3515.
Bunch, T.E., Keil, K., Snetsinger, K.G. (1967) Chromite composition in relation to chemistry and texture of ordinary chondrites. Geochimica et Cosmochimica Acta: 31(10) (Oct. 1967): 1569-1582.
Baldanza, B., Levi-Donati, G.R. (1971) Evidence of shock-metamorphic effects in the Ergheo Meteorite. Mineralogical Magazine: 38(294) (June 1971): 197-204.
Ramdohr, P. (1973) The Opaque Minerals in Stony Meteorites. Elsevier Publishing Company, Amsterdam, London, New York, 245 pages.
Wasson, J., Wang, S. (1991) The histories of ordinary chondrite parent bodies: U,Th-He age distributions. Meteoritics: 26(2) (June 1991): 161-167.
Alexeev, V.A. (1998) Parent bodies of H and L chondrites: Times of catastrophic events. Meteoritics & Planetary Science: 33(1) (Jan 1998).
Grady, M.M. (2000) Catalogue of Meteorites (5/e). Cambridge University Press, Cambridge, New York, Oakleigh, Madrid, Cape Town, 689 pages.
External Links
http://www.lpi.usra.edu/meteor/metbull.php - MeteoriticalBulletinDatabase
http://www.lpi.usra.edu/meteor/metbull.php?code=10044 - Ergheo@MetBullDatabase
http://www.encyclopedia-of-meteorites.com/test/Ergheo_don_edwards.JPG - Ergheo specimen w. crust
http://www.encyclopedia-of-meteorites.com/test/ergheo_mark_bostick.JPG - Ergheo, polished surface
https://rruff.info/doclib/MinMag/Volume_38/38-294-197.pdf - Shock-metamorphism
http://www.lpi.usra.edu/meteor/metbull.php?code=10044 - Ergheo@MetBullDatabase
http://www.encyclopedia-of-meteorites.com/test/Ergheo_don_edwards.JPG - Ergheo specimen w. crust
http://www.encyclopedia-of-meteorites.com/test/ergheo_mark_bostick.JPG - Ergheo, polished surface
https://rruff.info/doclib/MinMag/Volume_38/38-294-197.pdf - Shock-metamorphism
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Ergheo meteorite, Lower Shabelle Region, Somalia